Abdominal symptoms are common; the history and physical examination are the basis for differential diagnosis and efficient use of laboratory and imaging studies. History must delineate the character and sequence of the symptoms. Familiarity with the anatomy and pathophysiology is essential for interpretation of abdominal findings. Repetition of the examination allows correlation of sequential findings with the evolution of symptoms.
The abdominal cavity is a shallow oval basin with a rigid W-shaped bottom of vertebral column and back muscles. Heavy flank muscles form the sides and the diaphragm and pelvic floor muscles close either end. The brim is formed by the lower rib margins at one end, and the pubic bones and ilia at the other. The cover is formed by the anterior abdominal wall muscles and fascia reinforced by two parallel rectus muscles attached to the ribs and pelvis.
The abdominal viscera are solid or hollow. The solid viscera are the liver, spleen, kidneys, adrenals, pancreas, ovaries, and uterus. These organs usually retain their shape and position as they enlarge. The liver, spleen, kidneys, and adrenals are shielded by the rib cage. The hollow viscera are the stomach, small intestines, colon, gallbladder, bile ducts, fallopian tubes, ureters, and urinary bladder. They are not palpable unless distended by gas, fluid or solid masses.
Two systems have been used to describe abdominal topography (Fig. 9-1). Most physicians prefer the simpler division into quadrants by an axial and a transverse line through the umbilicus which we use here.
Topographic Divisions of the Abdomen
On the left are the regions of the abdomen as defined in the Basle Nomina Anatomica terminology. Most of the nine regions are small, so that enlarged viscera and other structures occupy more than one. On the right is a simpler plan with four regions; it is preferred by most clinicians and is employed in this book. Many occasions arise when the quadrant scheme needs supplementing by reference to the epigastrium, the flanks, or the suprapubic region.
Major Systems and Their Physiology
The alimentary system converts ingested food into absorbable nutrients and fuels, and solid wastes. This complex process includes ingestion, mastication, bulk transport, storage, mechanical disruption, mixing, and digestion of ingested food and absorption of nutrients coordinated with production, storage, transport, and carefully timed release of digestive enzymes and bile acids. It is a functional barrier to microorganisms, parasites, and toxic molecules.
The alimentary system starts at the mouth and ends at the anus. The intra-abdominal portion extends from the gastroesophageal junction the diaphragmatic hiatus to the anus. Normal motility and digestion depend upon coordinated muscular and secretory activity mediated by local and systemic neural and endocrine systems. The bowel is a muscular ...